When South Africa joined the Commonwealth Advisory Aeronautical Research Council in 1948 it was decided that the study of atmospheric turbulence was the first research project which could be undertaken. Equipment for the recording of aircraft accelerations was not then available commercially so an apparatus was assembled in the laboratory of the National Physical Research Laboratory, use being made of a commercial sensing head and an oscillograph galvanometer with photographic recording. The apparatus weighed about fifteen pounds so it was used on Douglas DC-3 (Dakota) aircraft which were flying for the S. A. Air Force on routes from Pretoria, to Durban, Cape Town and return. This apparatus recorded altitude and vertical acceleration of the aircraft. At a later date a lightweight commercial instrument was purchased and fitted into a Douglas DC-4 (Skymaster) aircraft flying on the routes of S. A. Airways. This instrument recorded altitude, air speed, and vertical acceleration.